Polyembryony, Biology

Assignment Help:

Polyembryony

Presence of more than one embryo in a seed is termed polyembryony. The phenomenon, first discovered in orange seeds by Leeuwenhoek (1719), attracted considerable attention because of its potential for application in and horticulture. Polyembryony is broadly classified into simple and multiple, depending on whether the supernumerary arises in one or more embryo sacs in the ovule. Simple polyembryony may be sexual or asexual. In sexual polyembryony embryos may originate from the fertilized egg and synergids, or by budding or cleavage of the polyembryony cells or suspensor of the zygotic embryo.

Asexual embryos are produced within the embryo sac without fertilization. Embryos may also originate from diploid nucellar or integumentary cells of the ode and grow into the embryo sac. These embryos are termed adventive or sporophytic. Multiple polyembryonies involve production of accessory embryos from two or more embryo sacs in the same ovule. For example, in the sea Island cotton, Gossypium barbadense, fertilization of egg in one embryo sac stimulates the induction of embryo from an unfertilized egg in the adjacent embryo sac within the same ovule. Thus, diploid-haploid twin embryos are produced in the seed.


Related Discussions:- Polyembryony

Define absorption, Define Absorption, Transport and Excretion - Calcium? ...

Define Absorption, Transport and Excretion - Calcium? Calcium (Ca) in food occurs as calcium salts e.g. calcium phosphate or is associated with other dietary constituents e.g.

Explain adverse effects of imiquimod, Adverse Effects of Imiquimod Appl...

Adverse Effects of Imiquimod Application site reactions (irritation, pruritus, flaking, erosion) are generally mild to moderate in intensity and resolve within 2 weeks of cessa

How the molecule would increase in mass slightly, Suppose many of the atoms...

Suppose many of the atoms of nitrogen in a double-stranded molecule of DNA, of isotope N-14, were replaced with the isotope N-15. What afffect would this have? a) The nitrogeneo

How is the structure of a mitochondrion well adapted, How is the structure ...

How is the structure of a mitochondrion well adapted for the activities it carries out? The mitochondrial membranes segregate the enzymes and reactants of the Krebs cycle, faci

What are autotrophic beings? what are heterotrophic beings, What are autotr...

What are autotrophic beings? What are heterotrophic beings? The Autotrophic beings are those that can produce their own food that is that make organic material from inorganic c

Advantages of vegetative propagation, Advantages of vegetative propagation ...

Advantages of vegetative propagation Vegetative propagation helps to maintain fixed qualities and characteristic features of the parent plant. For Example in ornamental p

Explain the use of spectinomycin in pregnancy, Use of Spectinomycin in Preg...

Use of Spectinomycin in Pregnancy  Spectinomycin (Trobicin) can be used to treat pregnant women allergic to beta-lactam antibiotics, but is unreliable against pharyngeal gonoco

What is heterophagic intracellular digestion, Heterophagic intracellular di...

Heterophagic intracellular digestion is the breaking into minute substances of external substances engulfed in the cell by pinocytosis or phagocytosis. Phagosomes or pinosomes fuse

Mention the role o ribosome in peptide, Mention the role o ribosome's in pe...

Mention the role o ribosome's in peptide -bond formation .How does ATP facilitate it? a) Of springs derived by asexual reproduction are known as clones. Justify giving two R

Chronic bronchitis, Chronic Bronchitis Chronic Bronchitis is defined ...

Chronic Bronchitis Chronic Bronchitis is defined clinically as hypersecretion of mucus and recurrent episode of productive cough for a period of 3 months per year at least tw

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd